Electronic paper has become an important aspect of modern displays due to its advantaged features such as low power consumption, light weight and decreased thickness. An electronic paper includes a plurality of display units arranged in matrix, and each display unit is filled with colored particles carrying electric polarization. As a driving circuit provides electric potentials building electric field in each display unit by applied cross voltage, positions of particles in each display unit can be controlled to demonstrate various gray levels. Once a gray level is built in each display unit, it maintains for a long time (e.g., several hours) without fading even when power is no longer supplied, therefore the average power consumption of electronic paper can be reduced.
While driving gray level in each display unit by applied cross voltage, the driving circuit need to alternately provides a positive pulse and a negative pulse of different polarities with a positive voltage source and a negative voltage source respectively, and a difference between peak voltages of the positive pulse and the negative pulse is quite large, e.g., several tens of Volts. For a direct and immediate transition from the positive pulse to the negative pulse, the negative voltage source will drain a large amount of transient current for sustaining the difference between peak voltages of the positive and negative pulses. Similarly, for a direct transition from the negative pulse to the positive pulse, the positive voltage source needs to drain a large amount of current to sustain the peak voltage difference of the positive and the negative pulses. As large amount of transient current damages electrodes of electronic paper, yield of electronic papers is decreased. Also, operation voltages of driving circuit also become unstable, and the driving circuit is left vulnerable.